94 



MASS. EXPERIMENT STATION BULLETIN 204. 



History of the Plots ix 1919 and 1920. 



Corn and hay have been produced in the two years succeeding the 

 period that has been included in the tables and summary. In 1919 the 

 plots received an application of ground limestone at the rate of 2,000 

 pounds per acre. The lime was applied on the north half of each plot, 

 lengthwise of the area, instead of on the east half crosswise of the plots, 

 as heretofore. Plot G received no lime at this time, while its duplicate, 

 plot 8, was limed throughout. This rearrangement, it is believed, will 

 lead, as time passes, to a fairer comparison between the results obtained 

 with lime and those without lime. 



In the preparation of the preceding tables it was deemed best not to 

 include the crop of 1919, while that of 1920 had not yet been produced. 

 Now it seems proper to place them by themselves and amplify the results 

 alreadj' shown. 



The crop in 1919 was corn, which was grown as a preliminarj' step to 

 seeding with grass in the summer. Hay from mixed timothy, redtop and 

 clover was produced in 1920. The rainfall for the two years and the crop 

 yields are tabulated below. 



Table IX. — Crop Yields of 1919 and 1920 {Pounds per Acre). 



Table X. — RainfaU, Seasons of 1019 and 1920. 



The value of lime in conjunction with sulfate of ammonia is well shown 

 in these two crops. Although the ammonia produced an increase without 

 lime, the gain with lime was much greater. The absence of clover from 

 the unlimed areas in 1920 was striking, and redtop was the main crop 

 instead. On unlimed areas, with both corn and grass, sulfate of ammonia 

 showed injurious effects which are discussed later. 



